Mixing kettles are well known in the art and are utilized in the food, pharmaceutical, confectionary, and chemical industries for mixing various substances. These Kettles are typically hemispherical in shape and utilize one or more agitator arms, carrying various types of blades, which rotate within the kettle either about a vertical or a horizontal axis. One set of blades is ordinarily designed to scrape along the interior surface of the kettle to further enhance the mixing process and to prevent the product from burning on heated kettles. These scraper blades pivot on the agitator arms and are biased against the kettle interior surface by means of one or more springs. However, the use of such biasing springs has been found to be unsatisfactory because they occasionally break and become lost within the substance being mixed. This is of course completely unacceptable, particularly for food products.